The Design And Realization Of Personal Navigation System

As the digital era coming,the demand of personal location based services has increased constantly.How to provide trustworthy personal location services becomes one of the present research hotspots in navigation field.In this thesis,indoor and outdoor personal navigation technology is researched,and personal navigation system fixed on foot is designed and implemented from three aspects:hardware,software,and navigation algorithm.The main contents and results of this thesis are as follows:Referring to the current mainstream indoor and outdoor personal navigation scheme,the personal navigation system is designed,using TMS320C6748 as CPU,storing data by SD card,applying Wi-Fi as wireless communication,containing a 9-axis IMU,a Wi-Fi module,a GPS module and a pressure sensor,and the system hardware design frame is given.Multi-thread navigation software based on SYS/BIOS is introduced in order to promote the utilization rate of CPU resources.According to functional demand of navigation system,software is divided into several modules,and the cooperation way between modules is explained.The software system is implemented in detail through Starterware,SYS/BIOS,and other tools.The functional verification experiments show that software meets the functional requirements,and CPU Load is below 3%when just running driver software.According to the physical law of pedestrian,the dead reckoning algorithm based on Kalman filter is researched.The strapdown inertial navigation algorithm is used to update navigation result,and the Kalman filter is applied to correct velocity and attitude during the walking motion's stance phase.Magnetic compass is calibrated by ellipsoid fitting to correct the error of magnetic compass.To accurately detect the walking motion's stance phase,a corresponding algorithm is designed with multi detection criteria.A method to improve the correction effect of Kalman filter is proposed that measurement noise matrix is modified by covariance matrix,and solves the problem that the correction effect decreases with the iterations,The navigation ability of personal navigation system is tested through four experiments:standing,marking time,normal traveling,and straight round-trip traveling.The experimental results show that the navigation solution can correctly reflect the change of attitude,velocity and position.The position error is positively correlated with the walking distance and the number of walking steps,and the relative error between position error and travel distance is about 5%.The personal navigation system designed in this thesis can gain indoor and outdoor navigation information,and qualify basic navigation function.It provides a feasible navigation scheme for pedestrians in indoor and outdoor environment,and has certain application value.